Same type Has the same type of electrical appliances and is guaranteed to be assembled at the same time. For example, the front and rear 4 seats have heating functions, and theoretically there can be 4 modules, but in fact, it is not a single seat heating, but the front heating or front and rear heating modes. It is therefore possible to combine the heating of the front seats into one module, as well as the rear.
Functional coexistence Different types of electrical appliances, but connected to each other, serve the same function. For example, a car phone includes a microphone, buttons, radio, and antenna. If the modules are divided separately, 4 modules will be established. In practical applications, these four electrical appliances serve the function of the car phone at the same time, and only need to be divided into one module of the car phone.